Propeller



R. C. PRATT.

PROPELLER.

APPLICATION FILED APR.25, I9I8.

1,345,237. Patented June 29, 1920.

2 sHI-:ETssIIEET 2.

INVENTOR ATTOR N EY 4view of the propeller.

Aseries gof swinging blades.

`being 'made of lItOiBI'tlRT C. PRATT, OF CALHOUN, OKLAHOMA.

' rnornLLnR.

`Application filed AprI 25,

To all whom it may concern:

1 Be it known that LiRoERT C. PRATT, a

citizen of the United States, residing at VCalhoun, in the county of Le.k Flore and State of Oklahoma, have invented certain new and useful Improvements in Propellers, of which the following is a specification.

yThisinvention relates to propellers gen.- erally and particularly lfor application to steam and other power driven ships and has L for its object to provide a propeller which will be simple, strong and ldurable in construction7 efficient in operation, and fully Vadapted to the purpose for which it ,is de-y signed. .y Y .j

A further object `of the invention is to provide a thrust propeller. which may be placed at the bow or stern of a vessel, or both at thebow and stern and connected to suitable driving means which .will impart a fore and aft movement thereto to cause swinging blades mounted in thevpropeller to act against the water when the propeller is moved rearwardly and provide, a thrust which will 'impel the vessel in a yforward directiomthe blades upon reverse move ment of the propellerautomatically folding` to cause them to bear edge-wise against the water and so produce little resistanceto said reverse movement. Y f

With these objects in view, together with Iothers Vwhich will appear as thedescription proceeds, the inventionresides in the :novel I formation, combination,and arrangementof 3 5 parts, all as willbe described more fully hereinafter, `particularly ,pointed out inthe claims, and lillustrated inthe accompanying drawings, in which,-

Y Figure 1 is aside elevation o f the iinproved :propeller' in operative position upon a boat, one kof thefpropellers being shown at vthe bow and anotherat thestern of the boat.

Fig. -2 is a perspective view of the propeller disengaged'froin the boat andshown on a larger scale. Fig. 3 vis a vertical longitudinal sectional Fig. 4 is a similar viewof ythe,propeller Vshowing -a slight ,modificatiom and,

Fig. 5. is a longitudinal sectionalviewjLof a further modification `showing a plural ln'the drawings, 10 in frame of skeleton formation l said 4frame metal bars which shall /be both. stmng-1ight and #which also pref dicates .box-like l Specification of Letters Patent. Patented June 29, 1920 1918. Serial No. 230,773.

sent butlittle surface o f the water. this purpose the bars l1 which form the structurel of thefranie are shown as `made of angle iron which may be welded, riveted, or otherwise firmly secured at their meeting ends to produce the-boX-like frame shown in Fig. 2, having 'openfront and rear ends l2, open top and bottom 13 and open sides 14. As constructed, this frame may be moved through the water with greatv freedom and For cause very slight 4resistance owing to the small areaV which is in contact with the water. v l

For the purpose of .reciprocating `the frame 10, la rod 15 is rigidly connected to one end thereofvin any convenientand secure manner. One means vfoi' making this connectionis shown in the drawings and lconsists of a sleeve 16 fixed on the end of the rod y15 and having a plurality of radial arms 17 at the base thereof bolted lor riveted to j diagonal brace bars 18 that cross each other at one end of the frame as clearly shown in Figs. 2 and' of the drawings.` i f Within the frame 10 are hinged two swingingk blades 19 that are ladapted as ,the

propellergis moved in `a foreand aft .direcytion to swing open and .to close to properly function for forcing lthrough the water the boat upon ,which the propeller is mounted. The blades 19 are of a length to extend .en-

ytirely across the frame 10 andare hinged respectively near one edge in the sides of the frame at theftop and bottom thereof,

Vthe Widthof the blades'being such that their free edges ,are substantially together'in the center ofthe frame when in closed opera' tive position.

The pivotal axes 2O of ,the blades are in Vvertical' alinement so that when the blades closeto act on the water they present a substantially unbroken flat surface having-awidth and height equal to the like .dimensions of thefframe 10. .To limit the movementv of theblades 19 when fully open, stops 21 are mounted on the top and bottom frame bars 11, these stops being shown in 1 Fig. 3 in the form `of depending spring vfingers, while in Fig. 4 inwardly projecting pins areeinployed. Stop pins 22 may project inwardly from thelside bars 11a at the front of `the `frame 10 for the blades to strike when in closed position.

v Preferably the hinge` pivots 20- project lfrointhe sidejedgesof the blades 1,9 be` tween their meeting and the opposite edges as shownin FigsiQ/,B and 4; the pivots being at a greater distance from the meeting edges than from said opposite edges, an arrange-- ment which makes the blades very sensitive to the action of the fluid in which -they operate when the thrust is Amade. It also causes them to abuthmorel quietly against the stops. l e

In the form of propeller shown inFig. 3, the swinging blades 19 are hinged at the extreme forward end of the frame 10 and represent the preferred form of propeller which rwill 'be mounted at the how of the boat; for the propeller at the stern of the boat the slight modification shown in Fig. 4 is intended to be used. In this form the blades 19 are hinged midway the length 'of the frame 10 and at the top and bottom of the frame in vertical alinement but swing toward the end of the frame opposite that to'which the thrust rod 15 'is attached and in this position they move freely through the water. Upon movement of the proy w peller in the opposite direction or stern-wise,

the blades close and stand in alinement as shown in dotted lines in Fig. 4, being maintained in this position by stop rpins 23` projecting inwardlyv from horizontal bars 24 on the side of the frame 10. `It will be noted that the stops 21Y which limit the opening movement'of the blades are nearer to each other than the pivots., 20 of the bladesl themselves. This results in preventing the blades from vopening into planes strictly at right angles to the plane they occupy when closed, or in other words when the blades are open 'they do not'stand strictly along the line of progress. Asa result, when kthe propeller is again forced tothe rear, the

free edges ofthe blades are caught on thev watery Aand the blades are 'forced closed against the stops 2 2 or 23. i

A propeller such as described may be mounted at the bow or the stern of the boat, or both at the bow-` and stern, being used singly or in pairs at either or bothl ends of the boat and when used vin pairs they operatealternately.` When a' boat is provided with a propeller at the bow and anotherV at the stern as in Fig. 1 the thrust rods .15 are mounted to slide horizontally in suitably placed bearings 25, the rods 15 being in Aalineme'nt and their inner ends terminating adJacent a steam, Igas or other motive powerl engine, not4 shown. This engine drives a `power shaft 26.to which is keyed a crank or crank disk 27,. to the crank pin 28 of y,which arefpivoted two connecting rods29 that extend in opposite directions from said I crankpin'to the inner endsof the two thrust rods 15 to which they arepivoted as at 30. In operation, the engine drives the shaft y 26 and rotates fthe crank 27kwhich through the connecting rods 29 reciprocate'the thrust rod 15 and the propellers' mounted thereon 1n a fore-and aft direction. Ontheforappended iclaims.

e V1. A device ofth ward movement ofthe propellers, the blades f- 19 of the forward. propeller illustrated in Fig. 3 and the rear'propeller shown in Fig. 4, swing to the rear or in openposition and lie substantially in line with the direction of movement of the propellers and so offer closed positionv againstthe stops 22 and23 1 so that they present at each end ofthe boat an extensive rigid surface that, pressing against the water, forces the'boat in a forward direction. By yduplicating the Vpropellers at the bow'and stern and operatingl them alternately, a practically continuous pressureV against the .water in a rearward directionv Y will roperateto force the boatfitted with thesepropellers in a forward direction and at a rapid rate of speed. If desired, the

propeller frame 1() may be equipped withy two or more sets of blades 19 as in Fig. 5,-

the setsbeing placed one behind the other `as shown to operate -in` unison.Y In this form, stop pins 31 projectinwardly from Vthe frame and serve 4toY limit the open position of one set of blades andthe closed position' ofthe blades next in rear. 'By constructing the frame 10` as shownrin skeleton Y form, no impediment is offered to'access of j water tothe blades of the'r'propeller and'so great rapidity of movement is'possibl'e and consequentlyrapid movement of the boat throughthe water. y i v A propeller of this type if made of alu! minum or some other light strong metal can be mounted' on aero'planesy andform 'the Vdriving meansrtherefor in place ofV theV screw propellernowV in common use ;V the propeller may also be usedto submerge or raise boats, pump water, as aventilator for 110 houses,l mines and other places7 and wherev ever the screw propeller lisl nowrused'rthe'..

present .device-'may be substituted therefor.

`The foregoingdescription andthe drawings havereference to what may becon'sidered the preferred,v or approved, form ofm'y. invention. lIt is to be-unde'rstood that I may make such changes inconstructionand arrangement and combination ofy parts, ma-v terials, dimensions, et cetera, asv maylr prove expedient and fall within -sthe scope ofthe- Having thus? fully described Vmy :invention, what I claimas new-and desire to se-ff:

V'cure by LetterslIatent, is:

class described comprising a reciprocating rod,` aV frame' comprising a pair of upper horizontally extending and'spaced apartbars and a pair'of lower :horizontally "extending, and spaced 2. A device of the class described coIn,

prising a reciprocating rod, a box like frame comprising a pair of upper horizontally ex-Y tending and spaced apart bars, and a pair of lower horizontally extending and spaced apart bars, vertical bars connecting the ends or said horizontal bars, means provided for connecting one end of said reciprocating rod to said frame, blades hingedlymounted within said frame so as to pivotbetween said horizontal bars, means carried by said frame for stopping said blades when in a closed position.

3. A device'of the class described comprising ya reciprocating rod, a box like frame, means for connecting said box like frame to one end of said reciprocating rod, j

said frame comprising a pair of upper horizontally extending and spaced apart bars, and a pair of lower horizontally extending and spaced apart bars, vertical bars connecting the ends of said horizontal bars, rods connecting the upper bars with their cor- 1 responding lower bars, said rods provided with spaced apart stop pins adjacent their central portionsblades pivotally mounted between said horizontally extending bars vand adjacent said rods, and abutments provided upon said horizontal bars sol that when said bladesare in an open position .Y

they will converge toward each other, thereby Yhaving a tendency to take a closed position vwhen said frame is reciprocated.

5In testimony whereof I aix my signature in presence of two Witnesses.

- ROBERT C. PRATT.

Witnesses: j

OSCAR WILLIGE, F. M. WILSON. 

